Flickering in a time direction of random noise present in a video, mosquito noise shown in compressed moving images or the like causes deterioration of image quality. For this reason, a method of removing such noise has been developed. An ε filter is a filter for determining a difference of a pixel value between a process target pixel and a reference pixel used in averaging by a threshold value (ε) to acquire an average of the reference pixel whose pixel value difference is equal to or less than the threshold value and the target pixel. The ε filter can prevent the image quality from deteriorating when impulse noise is present or when an object of an image in which the process target pixel and the reference pixel are different is represented when there is a change of the pixel value exceeding the threshold value.
In the compressed moving images, a method of applying the ε filter in the time direction in order to suppress the flickering and to generate a smooth image has been proposed.
In the related art, it may be difficult to solve the flickering in the time direction in the area with motion in the video.